The instant invention relates to easy open container components such as container end closure members and the like. More particularly it is concerned with providing an improved depressible combination pressure release, vent and pouring opening tab for container components such as can end closures that includes multiple tab sections such as primary and secondary tab sections. The secondary tab section is connected to the primary section by an improved weakened hinge portion. This hinge portion facilitates either the simultaneous selective depression of the various tab sections or only the secondary tab section in order to obtain an initial separation of the tab from the container component with which it is associated and to controllably relieve the internal pressure generated by the contents of the container within the container.
Significant problems involved in the construction and use of depressible or push button tabs for beer and effervescent beverage containers, and the like, concern the controlled relief of internal pressures and the venting of the container's interior to the atmosphere during initial opening of the container equipped with such tabs in order to avoid undesirable outward spraying, splattering and foaming of the container's contents, etc.
Past efforts to avoid the aforesaid problems have included the use of a pair of differentially sized openings in a can top, each of which was covered by a separate depressible push button. The smaller opening and its associated push button provided the pressure release and atmospheric vent opening means and the larger opening provided the primary pouring opening. The smaller push button was adapted to be opened first and because of its smaller size required less force. This type of prior art push button or depressible opener tab container end is illustrated, for example, in U.S. Pat. Nos. 3,902,627; 3,958,717; 3,972,445; 3,886,881; 4,033,275; U.S. Pat. Nos. D. 226,171 and 233,137; British patent specifications Nos. 1,357,468 of June 19, 1954 and 1,407,806 of Sept. 5, 1975 and Australian Pat. No. 475,951.
It has been further suggested that such prior art small pressure release and vent openings be incorporated in the principal of large depressible tab structure of an easy open can end. Prior art patents illustrating this type of can end construction, for example, include U.S. Pat. Nos. 3,741,432 and 3,794,206 as well as German Offenlegungsschrift No. 2,421,314 published Nov. 14, 1974 and British specification No. 1,444,470 of July 28, 1976. In these instances the smaller depressible tab was connected to the main or larger depressible tab of which it forms a part by a simple hinge arrangement.
Another approach to solving the pressure relief and venting problems of easy open cans for beer and effervescent beverages is contained in the patent application of John S. Rhoades, Ser. No. 830,970, filed Sept. 6, 1977, in which the proposal is made to equip the nose portion of a depressible easy open container tab with a unique pressure release and venting notch means.